| Family: |
Crenuchidae (South American darters), subfamily: Characidiinae |
| Max. size: |
2.66 cm SL (male/unsexed) |
| Environment: |
benthopelagic; freshwater; pH range: 6.2 - 6.3; depth range 1 - 2 m |
| Distribution: |
South America: Rio Aruã, tributary of the Rio Tapajós basin, lower Amazon in Brazil. |
| Diagnosis: |
Dorsal soft rays (total): 12-13; Anal soft rays: 8-9; Vertebrae: 34-34. It is diagnosed from other species of Characidium, except C. serrano and C. heirmostigmata, by having anteriorly oblique, midlateral bands centered on lateral line or just ventral thereof and not reaching either the dorsum or the ventrum, anterior bands. It differs from from C. serrano and C. heirmostigmata by having the following characters: 3 scales above and 3 below the lateral line (vs. 4 or 5 above and 4 or 5 below the lateral line in C. serrano and C. heirmostigmata); 10 scales around the caudal peduncle (vs. 12 in C. serrano and C. heirmostigmata); and snout length 15.0-18.8% HL (vs. 23.4-26.9% HL in C. serrano and 20.3- 27.8% HL in C. heirmostigmata). It can be further distinguished from C. heirmostigmata by having 12-15 oblique bars (vs. 8-11), 8 or 9 anal-fin rays (vs. 10 or 11), 10 or 11 pectoral-fin rays (vs. 13 or 14), and head length 25.7-29.2% SL (vs. 22.4-24.6% SL). It can be further separated from C. serrano by having 29-33 scales on the lateral line (vs. 37-39) and interorbital distance 19.0-25.0% HL (vs. 11.9-17.2 HL). This species is slightly similar to the psammophile species C. heinianum, C. longum, C. pellucidum, and C. pteroides because of its reticulated color pattern. However, it is distinguished from those species by the presence of the anteriorly oblique bars. It can be further distinguished from C. longum by having 10 or 11 pectoral-fin rays (vs. 13 or 14), 10 scale series around the caudal peduncle (vs. 12), body depth at dorsal-fin origin 18.9-25.7% SL (vs. 9.3-15.8% SL), and body depth at anal-fin origin 12.2-17.8% SL (vs. 7.5-11.0% SL); from another psammophile species, Geryichthys sterbai, by the presence of the adipose fin (vs. absence), by the presence of ectopterygoid teeth (vs. absence), by the 10 scale series around the caudal peduncle (vs. 12); and by absence of rhomboidal bars (vs. presence) (Ref. 93226). |
| Biology: |
Inhabits stream with shallow margins about 1-1.8 m deep, dense aquatic vegetation, sandy bottom and margins composed of decaying plant matter (Ref. 93226). |
| IUCN Red List Status: |
Least Concern (LC); Date assessed: 07 November 2018 Ref. (130435)
|
| Threat to humans: |
harmless |
| Country info: |
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